Astronaut James F. Reilly participated in the first ever space walk to egress from the International Space Station (ISS) by utilizing the newly-installed Joint Airlock Quest. The Joint Airlock is a pressurized flight element consisting of two cylindrical chambers attached end-to-end by a cornecting bulkhead and hatch. Once installed and activated, the ISS Airlock becomes the primary path for ISS space walk entry and departure for U.S. spacesuits, which are known as Extravehicular Mobility Units (EMUs). In addition, it is designed to support the Russian Orlan spacesuit for extravehicular activity (EVA). The Joint Airlock is 20-feet long, 13- feet in diameter and weighs 6.5 tons. It was built at the Marshall Space Flight Center (MSFC) by the Space Station prime contractor Boeing. The ISS Airlock has two main components: a crew airlock and an equipment airlock for storing EVA and EVA preflight preps. The Airlock was launched on July 21, 2001 aboard the Space Shuttle Orbiter Atlantis for the STS-104 mission.